mesa-drm/amdgpu/amdgpu_vamgr.c
Samuel Pitoiset 8cc2d09c29 amdgpu: reserve half of the addr space to implement a workaround for PRT
On GFX6-GFX12, except GFX9, SMEM loads on NULL PRT pages would just
fault and hang the GPU. The better workaround that we found is to split
the address space in two equal parts "LOW"/"HIGH", here's more details:

To workaround that, the driver splits the total VA space in half, so
that a single bit controls whether it's the "HIGH" or the "LOW"
address space. Every sparse residency buffer allocations that might
be used with SMEM get two allocations:

- the "HIGH" address space is mapped normally and its VA is returned
  to the application.
- the "LOW" address space is explicitly mapped to a zero-initialized
  buffer when it's allocated or when it's unmapped.

Other buffer allocations are always allocated in the "LOW" address.

The driver also creates a zero-allocated BO that will be used to map
partially resident buffers at creation and when explicitly unmapped.
The size is arbitrary but it seems that allocating 8MiB is perfectly
reasonable and fast enough in most cases. This BO is marked as
read-only for the GPU because the backend compilers don't use SMEM
stores.

For example this makes the "LOW" half of the HIGH VA range like
[0xffff800100000000,0xffffbfffffbfe000], and the "HIGH" half is left
for PRT.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
2026-04-27 09:59:32 +02:00

406 lines
11 KiB
C

/*
* Copyright 2014 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "amdgpu.h"
#include "amdgpu_drm.h"
#include "amdgpu_internal.h"
#include "util_math.h"
drm_public int amdgpu_va_range_query(amdgpu_device_handle dev,
enum amdgpu_gpu_va_range type,
uint64_t *start, uint64_t *end)
{
if (type != amdgpu_gpu_va_range_general)
return -EINVAL;
*start = dev->dev_info.virtual_address_offset;
*end = dev->dev_info.virtual_address_max;
return 0;
}
drm_private void amdgpu_vamgr_init(struct amdgpu_bo_va_mgr *mgr, uint64_t start,
uint64_t max, uint64_t alignment)
{
struct amdgpu_bo_va_hole *n;
mgr->va_max = max;
mgr->va_alignment = alignment;
list_inithead(&mgr->va_holes);
pthread_mutex_init(&mgr->bo_va_mutex, NULL);
pthread_mutex_lock(&mgr->bo_va_mutex);
n = calloc(1, sizeof(struct amdgpu_bo_va_hole));
n->size = mgr->va_max - start;
n->offset = start;
list_add(&n->list, &mgr->va_holes);
pthread_mutex_unlock(&mgr->bo_va_mutex);
}
drm_private void amdgpu_vamgr_deinit(struct amdgpu_bo_va_mgr *mgr)
{
struct amdgpu_bo_va_hole *hole, *tmp;
LIST_FOR_EACH_ENTRY_SAFE(hole, tmp, &mgr->va_holes, list) {
list_del(&hole->list);
free(hole);
}
pthread_mutex_destroy(&mgr->bo_va_mutex);
}
static drm_private int
amdgpu_vamgr_subtract_hole(struct amdgpu_bo_va_hole *hole, uint64_t start_va,
uint64_t end_va)
{
if (start_va > hole->offset && end_va - hole->offset < hole->size) {
struct amdgpu_bo_va_hole *n = calloc(1, sizeof(struct amdgpu_bo_va_hole));
if (!n)
return -ENOMEM;
n->size = start_va - hole->offset;
n->offset = hole->offset;
list_add(&n->list, &hole->list);
hole->size -= (end_va - hole->offset);
hole->offset = end_va;
} else if (start_va > hole->offset) {
hole->size = start_va - hole->offset;
} else if (end_va - hole->offset < hole->size) {
hole->size -= (end_va - hole->offset);
hole->offset = end_va;
} else {
list_del(&hole->list);
free(hole);
}
return 0;
}
static drm_private int
amdgpu_vamgr_find_va(struct amdgpu_bo_va_mgr *mgr, uint64_t size,
uint64_t alignment, uint64_t base_required,
bool search_from_top, uint64_t *va_out)
{
struct amdgpu_bo_va_hole *hole, *n;
uint64_t offset = 0;
int ret;
alignment = MAX2(alignment, mgr->va_alignment);
size = ALIGN(size, mgr->va_alignment);
if (base_required % alignment)
return -EINVAL;
pthread_mutex_lock(&mgr->bo_va_mutex);
if (!search_from_top) {
LIST_FOR_EACH_ENTRY_SAFE_REV(hole, n, &mgr->va_holes, list) {
if (base_required) {
if (hole->offset > base_required ||
(hole->offset + hole->size) < (base_required + size))
continue;
offset = base_required;
} else {
uint64_t waste = hole->offset % alignment;
waste = waste ? alignment - waste : 0;
offset = hole->offset + waste;
if (offset >= (hole->offset + hole->size) ||
size > (hole->offset + hole->size) - offset) {
continue;
}
}
ret = amdgpu_vamgr_subtract_hole(hole, offset, offset + size);
pthread_mutex_unlock(&mgr->bo_va_mutex);
*va_out = offset;
return ret;
}
} else {
LIST_FOR_EACH_ENTRY_SAFE(hole, n, &mgr->va_holes, list) {
if (base_required) {
if (hole->offset > base_required ||
(hole->offset + hole->size) < (base_required + size))
continue;
offset = base_required;
} else {
if (size > hole->size)
continue;
offset = hole->offset + hole->size - size;
offset -= offset % alignment;
if (offset < hole->offset) {
continue;
}
}
ret = amdgpu_vamgr_subtract_hole(hole, offset, offset + size);
pthread_mutex_unlock(&mgr->bo_va_mutex);
*va_out = offset;
return ret;
}
}
pthread_mutex_unlock(&mgr->bo_va_mutex);
return -ENOMEM;
}
static drm_private void
amdgpu_vamgr_free_va(struct amdgpu_bo_va_mgr *mgr, uint64_t va, uint64_t size)
{
struct amdgpu_bo_va_hole *hole, *next;
if (va == AMDGPU_INVALID_VA_ADDRESS)
return;
size = ALIGN(size, mgr->va_alignment);
pthread_mutex_lock(&mgr->bo_va_mutex);
hole = container_of(&mgr->va_holes, hole, list);
LIST_FOR_EACH_ENTRY(next, &mgr->va_holes, list) {
if (next->offset < va)
break;
hole = next;
}
if (&hole->list != &mgr->va_holes) {
/* Grow upper hole if it's adjacent */
if (hole->offset == (va + size)) {
hole->offset = va;
hole->size += size;
/* Merge lower hole if it's adjacent */
if (next != hole &&
&next->list != &mgr->va_holes &&
(next->offset + next->size) == va) {
next->size += hole->size;
list_del(&hole->list);
free(hole);
}
goto out;
}
}
/* Grow lower hole if it's adjacent */
if (next != hole && &next->list != &mgr->va_holes &&
(next->offset + next->size) == va) {
next->size += size;
goto out;
}
/* FIXME on allocation failure we just lose virtual address space
* maybe print a warning
*/
next = calloc(1, sizeof(struct amdgpu_bo_va_hole));
if (next) {
next->size = size;
next->offset = va;
list_add(&next->list, &hole->list);
}
out:
pthread_mutex_unlock(&mgr->bo_va_mutex);
}
drm_public int amdgpu_va_range_alloc(amdgpu_device_handle dev,
enum amdgpu_gpu_va_range va_range_type,
uint64_t size,
uint64_t va_base_alignment,
uint64_t va_base_required,
uint64_t *va_base_allocated,
amdgpu_va_handle *va_range_handle,
uint64_t flags)
{
return amdgpu_va_range_alloc2(&dev->va_mgr, va_range_type, size,
va_base_alignment, va_base_required,
va_base_allocated, va_range_handle,
flags);
}
drm_public int amdgpu_va_range_alloc2(amdgpu_va_manager_handle va_mgr,
enum amdgpu_gpu_va_range va_range_type,
uint64_t size,
uint64_t va_base_alignment,
uint64_t va_base_required,
uint64_t *va_base_allocated,
amdgpu_va_handle *va_range_handle,
uint64_t flags)
{
struct amdgpu_bo_va_mgr *vamgr;
bool search_from_top = !!(flags & AMDGPU_VA_RANGE_REPLAYABLE);
int ret;
/* Clear the flag when the high VA manager is not initialized */
if (flags & AMDGPU_VA_RANGE_HIGH && !va_mgr->vamgr_high_32.va_max)
flags &= ~AMDGPU_VA_RANGE_HIGH;
if (flags & AMDGPU_VA_RANGE_HIGH) {
if (flags & AMDGPU_VA_RANGE_32_BIT)
vamgr = &va_mgr->vamgr_high_32;
else
vamgr = &va_mgr->vamgr_high;
} else {
if (flags & AMDGPU_VA_RANGE_32_BIT)
vamgr = &va_mgr->vamgr_32;
else
vamgr = &va_mgr->vamgr_low;
}
va_base_alignment = MAX2(va_base_alignment, vamgr->va_alignment);
size = ALIGN(size, vamgr->va_alignment);
ret = amdgpu_vamgr_find_va(vamgr, size,
va_base_alignment, va_base_required,
search_from_top, va_base_allocated);
if (!(flags & AMDGPU_VA_RANGE_32_BIT) && ret) {
/* fallback to 32bit address */
if (flags & AMDGPU_VA_RANGE_HIGH)
vamgr = &va_mgr->vamgr_high_32;
else
vamgr = &va_mgr->vamgr_32;
ret = amdgpu_vamgr_find_va(vamgr, size,
va_base_alignment, va_base_required,
search_from_top, va_base_allocated);
}
if (!ret) {
struct amdgpu_va* va;
va = calloc(1, sizeof(struct amdgpu_va));
if(!va){
amdgpu_vamgr_free_va(vamgr, *va_base_allocated, size);
return -ENOMEM;
}
va->address = *va_base_allocated;
va->size = size;
va->range = va_range_type;
va->vamgr = vamgr;
*va_range_handle = va;
}
return ret;
}
drm_public int amdgpu_va_range_free(amdgpu_va_handle va_range_handle)
{
if(!va_range_handle || !va_range_handle->address)
return 0;
amdgpu_vamgr_free_va(va_range_handle->vamgr,
va_range_handle->address,
va_range_handle->size);
free(va_range_handle);
return 0;
}
drm_public uint64_t amdgpu_va_get_start_addr(amdgpu_va_handle va_handle)
{
return va_handle->address;
}
drm_public amdgpu_va_manager_handle amdgpu_va_manager_alloc(void)
{
amdgpu_va_manager_handle r = calloc(1, sizeof(struct amdgpu_va_manager));
return r;
}
drm_public void amdgpu_va_manager_init(struct amdgpu_va_manager *va_mgr,
uint64_t low_va_offset, uint64_t low_va_max,
uint64_t high_va_offset, uint64_t high_va_max,
uint32_t virtual_address_alignment)
{
amdgpu_va_manager_init2(va_mgr, low_va_offset, low_va_max,
high_va_offset, high_va_max,
virtual_address_alignment, 0);
}
drm_public void amdgpu_va_manager_init2(struct amdgpu_va_manager *va_mgr,
uint64_t low_va_offset, uint64_t low_va_max,
uint64_t high_va_offset, uint64_t high_va_max,
uint32_t virtual_address_alignment,
uint32_t flags)
{
uint64_t start, max;
va_mgr->address_prt_wa_control_bit = ~0;
start = low_va_offset;
max = MIN2(low_va_max, 0x100000000ULL);
amdgpu_vamgr_init(&va_mgr->vamgr_32, start, max,
virtual_address_alignment);
start = max;
if ((flags & AMDGPU_VA_MGR_RESERVE_HALF_VA_FOR_PRT) && !high_va_max) {
/* Reserve the half VA range for PRT by splitting it in two
* equal halves where one bit controls whether it's the LOW or
* HIGH half.
*/
va_mgr->address_prt_wa_control_bit = util_last_bit64(low_va_offset ^ low_va_max) - 1;
max = low_va_max ^ (1ull << va_mgr->address_prt_wa_control_bit);
} else {
max = MAX2(low_va_max, 0x100000000ULL);
}
amdgpu_vamgr_init(&va_mgr->vamgr_low, start, max,
virtual_address_alignment);
start = high_va_offset;
max = MIN2(high_va_max, (start & ~0xffffffffULL) + 0x100000000ULL);
amdgpu_vamgr_init(&va_mgr->vamgr_high_32, start, max,
virtual_address_alignment);
start = max;
if ((flags & AMDGPU_VA_MGR_RESERVE_HALF_VA_FOR_PRT) && high_va_max) {
/* Reserve the half VA range for PRT by splitting it in two
* equal halves where one bit controls whether it's the LOW or
* HIGH half.
*/
va_mgr->address_prt_wa_control_bit = util_last_bit64(high_va_offset ^ high_va_max) - 1;
max = high_va_max ^ (1ull << va_mgr->address_prt_wa_control_bit);
} else {
max = MAX2(high_va_max, (start & ~0xffffffffULL) + 0x100000000ULL);
}
amdgpu_vamgr_init(&va_mgr->vamgr_high, start, max,
virtual_address_alignment);
}
drm_public void amdgpu_va_manager_deinit(struct amdgpu_va_manager *va_mgr)
{
amdgpu_vamgr_deinit(&va_mgr->vamgr_32);
amdgpu_vamgr_deinit(&va_mgr->vamgr_low);
amdgpu_vamgr_deinit(&va_mgr->vamgr_high_32);
amdgpu_vamgr_deinit(&va_mgr->vamgr_high);
}
drm_public int amdgpu_va_manager_query_sw_info(struct amdgpu_va_manager *va_mgr,
enum amdgpu_va_manager_sw_info info,
void *value)
{
uint32_t *val32 = (uint32_t*)value;
switch (info) {
case amdgpu_va_manager_sw_info_address_prt_wa_control_bit:
*val32 = va_mgr->address_prt_wa_control_bit;
return 0;
}
return -EINVAL;
}